The present invention relates to phthalocyanine compounds, more specifically iodogallium phthalocyanine compound, bromogallium phthalocyanine compound and zirconium phthalocyanine compound, having novel crystal forms. The present invention further relates to a process for producing the phthalocyanine compounds and an electrophoto-graphic photosensitive member using the phthalocyanine compounds.
Hitherto, phthalocyanine pigments have been noted and studied not only as coloring agents but also as electronic materials for constituting electrophotographic photosensitive members, solar batteries, photosensors, etc.
On the other hand, non-impact type printers utilizing electrophotography have been widely used as terminal printers in recent years, in place of conventional impact type printers. These printers are principally constituted as laser beam printers using a laser as a light source. As the light source, a semiconductor laser has been predominantly used in view of its cost and apparatus size. A semiconductor laser principally used at present has an emission wavelength in a long wavelength region around 790 nm, so that electrophotographic photoconductors having a sufficient sensitivity to such a long-wavelength light have been developed.
The sensitivity region of an electrophotographic photoconductor principally varies depending on a charge-generating material, and many studies have been made on charge-generating materials having a sensitivity to a long-wavelength light including metallic phthalocyanines and non-metallic phthalocyanines, such as aluminum chlorophthalocyanine, chloroindium phthalocyanine, oxyvanadium phthalocyanine, hydroxygallium phthalocyanine, chlorogallium phthalocyanine, magnesium phthalocyanine, and oxytitanium phthalocyanine.
Many of these phthalocyanine compounds are known to have various crystal forms. For example, non-metallic phthalocyanine is known to have xcex1-form, xcex2-form, xcex3-form, xcex4-form, xcex5-form, "khgr"-form, xcfx84-form, etc., and copper phthalocyanine is known to have xcex1-form, xcex2-form, xcex3-form, xcex5-form, "khgr"-form, etc. Specific examples of these phthalocyanine compounds are disclosed in, e.g., Japanese Laid-Open Patent Application (JP-A) 50-38543, JP-A 51-108847, and JP-A 53-37423. Oxytitaniun phthalocyanines are reported in JP-A 61-217050, JP-A 61-239248, JP-A 62-67094, JP-A 64-17066 and JP-A 3-128973. Further, gallium phthalocyanines are disclosed in JP-A 5-98181 and JP-A 5-263007 with respect to chlorogallium phthalocyanine and hydroxygallium phthalocyanine together with their crystal forms. Further, iodogallium phthalocyanine is disclosed in JP-A 60-59354, and bromogallium phthalocyanine is disclosed in JP-A 57-148745 but with no specific disclosure regarding their crystal forms.
However, many electrophotographic photosensitive members using such known phthalocyanine compounds only show a low sensitivity and are liable to cause fluctuation in dark-part potential and light-part potential during repetitive use.
An object of the present invention is to provide phthalocyanine compounds having a novel crystal form, and a process producing the compounds.
Another object of the present invention is to provide an electrophotographic photosensitive member having a very high sensitivity to long-wavelength light and having excellent potential stability.
According to the present invention, there is provided iodogallium phthalocyanine having a crystal form selected from those characterized by X-ray diffraction patterns (a)-(e) shown below respectively obtained by a CuKxcex1 characteristic X-ray diffraction method:
(a) having a strongest peak at a Bragg angle (2xcex8xc2x10.2 deg.) of 9.6 deg. and free from another peak having an intensity of 30% or more of that of the strongest peak,
(b) having a strongest peak and a second strongest peak at Bragg angles (2xcex8xc2x10.2 deg.) of 9.4 deg. and 27.1 deg. wherein the second strongest peak has an intensity of at least 30% of that of the strongest peak,
(c) having a strongest peak and a second strongest peak at Bragg angles (2xcex8xc2x10.2 deg.) of 7.5 deg. and 27.7 deg.,
(d) having a strongest peak and a second strongest peak at Bragg angles (2xcex8xc2x10.2 deg.) of 7.5 deg. and 26.4 deg., and
(e) having (e)(i) a strongest peak, a second strongest peak and a third strongest peak at Bragg angles (2xcex8xc2x10.2 deg.) of 9.6 deg., 8.8 deg. and 27.2 deg., respectively, or (e) (ii) a strongest peak and a second strongest peak at Bragg angles (2xcex8xc2x10.2 deg.) of 27.2 and 8.8 deg., respectively.
According to the present invention, there is also provided bromogallium phthalocyanine having a crystal form selected from those represented by X-ray diffraction patterns (f)-(j) shown below respectively obtained by a CuKxcex1 characteristic X-ray diffraction method:
(f) having a strongest peak at a Bragg angle (2xcex8xc2x10.2 deg.) of 27.3 deg. and free from another peak having an intensity of 30% or more of that of the strongest peak,
(g) having a strongest peak and a second strongest peak at Bragg angles (2xcex8xc2x10.2 deg.) of 9.0 deg. and 27.1 deg., wherein the second strongest peak has an intensity of at least 30% of that of the strongest peak,
(h) having a strongest peak and a second strongest peak at Bragg angles (2xcex8xc2x10.2 deg.) of 7.4 deg. and 27.9 deg.,
(i) having a strongest peak and a second strongest peak at Bragg angles (2xcex8xc2x10.2 deg.) of 7.5 deg. and 26.4 deg., and
(j) having a strongest peak and a second strongest peak at Bragg angles (2xcex8xc2x10.2 deg.) of 6.9 deg. and 26.7 deg.
Such iodo-(or bromo-)gallium phthalocyanine may effectively be produced through a process comprising: reacting chlorogallium phthalocyanine or hydroxygallium phthalocyanine with hydroiodic (or hydrobromic) acid under milling or stirring.
According to the present invention, there is further provided zirconium phthalocyanine having a crystal form represented by an X-ray diffraction pattern having a strongest peak at a Bragg angle (2xcex8xc2x10.2 deg.) in a range of 7.0xe2x88x929.0 deg. as measured by a CuKxcex1 characteristic X-ray diffraction method.
Such zirconium phthalocyanine may effectively be produced through a process comprising milling or stirring zirconium phthalocyanine in an organic solvent.
According to the present invention, there is also provided an electrophotographic photosensitive member, comprising a support, and a photosensitive layer formed on the support and containing one of the above-mentioned iodogallium phthalocyanine, bromogallium phthalocyanine and zirconium phthalocyanine.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.